Balloon catheter with stent and method for manufacturing it

ABSTRACT

The invention relates to a balloon catheter comprising a catheter tube, an inflatable balloon, the ends of which are attached to the catheter tube, and a stent attached around the balloon. The stent extends at least partly along the length of the balloon. In an uninflated state, at least the outside surface of the balloon not covered by the stent is provided with a relief structure which is substantially disappeared in an inflated state of the balloon. The invention also relates to a method for manufacturing such a balloon catheter.

TECHNICAL FIELD

The present invention relates to a balloon catheter comprising acatheter tube, an inflatable balloon which at its ends is attached tothe catheter tube and a stent attached around the balloon, wherein thestent extends at least in part along the length of the balloon. Theinvention further relates to a method of manufacturing a ballooncatheter.

BACKGROUND INFORMATION

Balloon catheters of this type are generally known and are used fordilating vessels and lumina and for placing the stent in the dilatedvessel or lumen. In order to pass the balloon catheter easily and safelythrough the vessels and lumina and to position it at the required placefor dilatation, it is important that the balloon catheter has a smallprofile (outer diameter) and is sufficiently flexible.

The object of the invention is therefore to provide an improved ballooncatheter.

BRIEF SUMMARY OF THE INVENTION

The balloon catheter according to the inventions characterized in that,in an uninflated state, at least the outside surface of the balloon thatis not covered by the stent is provided with a relief structure which inan inflated state of the balloon is substantially disappeared.

Tests have shown that with a relief structure on the outside surface ofthe balloon a catheter is obtained that is more flexible than a standardballoon catheter. The balloon catheter according to the invention cantherefore be passed more easily and more safely through vessels andlumina to the point of dilatation. Because of its flexibility, thecatheter will be able to adapt better to a bend in a vessel or a lumen,thus reducing the risk of damage to the vessel or lumen.

The required relief structure may have different embodiments, butpreferably comprises at least one groove that extends at leasttransversely in the longitudinal direction of the balloon in order togive the catheter the required flexibility in a direction transverse tothe longitudinal direction thereof.

The groove preferably extends at a predetermined angle with respect tothe longitudinal direction of the balloon. According to a preferredembodiment, the groove extends helically from one end to the other endof the balloon, over the outside surface thereof.

According to another embodiment, the relief structure comprises two ormore grooves that extend helically from one end to the other end of theballoon, crossing each other. Flexible balloon catheter is obtainedwhich also has a relatively low profile.

The invention also relates to a method for producing a balloon cathetercomprising attaching the ends of an inflatable balloon to a cathetertube and placing a stent around the balloon, whereby according to theinvention at least the outside surface of the balloon not covered by thestent is provided with a relief structure.

According to a first embodiment, the outside surface of the balloon isfirst provided with the relief structure and then the stent is attachedaround the balloon. An additional advantage of this embodiment is that abetter fixing of the stent to the balloon is achieved. The improvementin fixing is due to the relief that makes the usual smooth surface ofthe balloon “rough”. The stent adheres better to this rough surface.

According to a second embodiment, the stent is first attached around theballoon and then the outside surface is provided with the reliefstructure. A more flexible stent fixing system is obtained because atleast the balloon material near the stent, both distally and proximally,is provided with a profile. Also, the stent placing system has obtaineda smaller profile compared with known stent placing systems.

The relief structure is preferably produced on the application of heatto the surface of the balloon in order to deform the elastic material ofthe balloon.

The relief structure is also preferably produced on the surface of theballoon by applying a high pressure to the inside of the balloon.

According to a very inexpensive method, the relief structure is producedon the surface of the balloon by winding a wire around the balloon inthe form of a helix.

According to another simple method, the relief structure is produced onthe surface of the balloon by taking up the balloon in acounter-pressure body that has the relief structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail on the basis of the drawingsattached. The drawings show:

FIG. 1A is a side view of a form of a balloon catheter in an uninflatedstate,

FIG. 1B is a side view of the catheter in FIG. 1A in an inflated state,

FIG. 2A is a side view of a second embodiment of a balloon catheterduring the execution of the method according to the invention, and

FIG. 2B is a side view of the final product of FIG. 2A.

DETAILED DESCRIPTION OF THE INVENTION

A balloon catheter according to the invention comprises a catheter tube1, an inflatable balloon 2, which at its ends 3 is attached to thecatheter tube 1, and a stent 6 attached around the balloon 2. The stent6 extends partly along the length of the balloon 2 such that with thecatheter, both distally and proximally next to the stent 6, balloonmaterial lies freely. In an uninflated state (FIG. 1A), the outsidesurface of the balloon 2 has a relief structure 4 that in the inflatedstate has virtually or completely disappeared (FIG. 1B). The reliefstructure 4 gives the distal end of the catheter its requiredflexibility.

In the embodiments shown, the relief structure 4 consists of two grooves5, which extend helically from one end 3 to the other end 3 of theballoon 2 and cross each other. The uninflated balloon 2 has therebyobtained a padded relief surface. It is also possible to provide arelief structure with a single helically shaped groove 5 whereby theuninflated balloon 2 displays a relief surface in the form of a helix.Other relief structures are of course possible, provided that the reliefstructure on the catheter creates the necessary flexibility in adirection transverse to the longitudinal direction of the balloon.

One way of obtaining the relief structure as shown in the drawings is bywinding a wire helically around the balloon 2. This wire may, forexample, be nylon wire or wire made of a different material thatcontracts somewhat on heating. After the wire has been wound around theballoon, a sleeve is pulled over the balloon. Subsequently, with theapplication of raised pressure to the inside of the balloon, the balloonis heated in such a way that in an uninflated state the balloon obtainsa relief structure that on dilating of the balloon at the dilation sitein the vessel or lumen will virtually or completely disappear. Thesleeve is then removed and the balloon catheter can be inserted into avessel or lumen.

The method according to the invention can be carried out in two ways. Inthe first way, the profile is first applied to the balloon by windingthis around with wire and heating it under internal pressure, and thenthe stent is placed on the balloon. This results in improved flexibilityand maneuverability of the distal part of the catheter. Better fixing ofthe stent on the “rough”, profiled surface of the balloon is alsoachieved. In the second way, a stent is first placed on the balloon andthen the complete distal part of the catheter, namely the balloonincluding the stent that has been placed in position, is wound aroundwith wire, preferably nylon wire. Then the whole assembly is heated at acertain internal pressure. Winding produces a helical profile in theballoon material next to the stent. At the same time the diameter of thecatheter with the stent is reduced because the nylon wire shrinks onheating. In a variation of this last method, first filler material 8 isplaced next to the stent, over which wire is then also wound (see FIG.2A). In the end this results in a small increase 7 in the balloonmaterial next to the stent 6 (see FIG. 2B), into which the ends of thestent 6 can be pressed. As a result the ends of the stent 6 are betterprotected if the stent placing system is passed in a curved trajectory.

Instead of winding the wire, the balloon may be placed in a mould, whichis provided with the relief pattern required, in order for it to obtain,under raised pressure and temperature, the relief structure required.

Before the balloon is provided with its relief structure, preferably itis folded in the usual way in order to reduce its profile. By applyingthe relief structure, the profile will be reduced as an additional,advantageous effect.

Note that, although it is not shown in the drawings, it is possible toprovide the outside surface of the balloon with various helical groovesthat cross each other. In addition to helical grooves, grooves of othershapes are also possible.

The balloon catheter may be used not only in cardiological but alsoradiological interventions.

1-7. (canceled)
 8. Method for producing a balloon catheter comprisingattaching opposite ends of an inflatable balloon to a catheter tube,attaching a stent around the balloon, and providing at least the outsidesurface of the balloon not covered by the stent with a relief structure.9. Method according to claim 8, whereby first the outside surface of theballoon is provided with the relief structure, and then the stent isattached around the balloon.
 10. Method according to claim 8, wherebyfirst the stent is attached around the balloon, and then the outsidesurface of the balloon is provided with the relief structure.
 11. Methodaccording to claim 10, whereby before the outside surface of the balloonis provided with the relief structure, obliquely to the stent, paddingis applied over the balloon and the stent.
 12. Method according to claim11, whereby the relief structure is applied to the surface of theballoon under the application of heat.
 13. Method according to claim 10,whereby the relief structure is applied to the surface of the balloonunder the application of heat.
 14. Method according to claim 9, wherebythe relief structure is applied to the surface of the balloon under theapplication of heat.
 15. Method according to claim 8, whereby the reliefstructure is applied to the surface of the balloon under the applicationof heat.
 16. Method according to claim 15, whereby the relief structureis applied to the surface of that balloon under the application ofraised pressure to the inside of the balloon.
 17. Method according toclaim 14, whereby the relief structure is applied to the surface of theballoon under the application of raised pressure to the inside of theballoon.
 18. Method according to claim 13, whereby the relief structureis applied to the surface of the balloon under the application of raisedpressure to the inside of the balloon.
 19. Method according to claim 12,whereby the relief structure is applied to the surface of the balloonunder the application of raised pressure to the inside of the balloon.20. Method according to claim 11, whereby the relief structure isapplied to the surface of the balloon under the application of raisedpressure to the inside of the balloon.
 21. Method according to claim 10,whereby the relief structure is applied to the surface of the balloonunder the application of raised pressure to the inside of the balloon.22. Method according to claim 9, whereby the relief structure is appliedto the surface of the balloon under the application of raised pressureto the inside of the balloon.
 23. Method according to claim 8, wherebythe relief structure is applied to the surface of the balloon under theapplication of raised pressure to the inside of the balloon.
 24. Methodaccording to claim 23, whereby the relief structure is applied to thesurface of the balloon by winding a wire helically around the balloon.25. Method according to claim 22, whereby the relief structure isapplied to the surface of the balloon by winding a wire helically aroundthe balloon.
 26. Method according to claim 21, whereby the reliefstructure is applied to the surface of the balloon by winding a wirehelically around the balloon.
 27. Method according to claim 20, wherebythe relief structure is applied to the surface of the balloon by windinga wire helically around the balloon.
 28. Method according to claim 19,whereby the relief structure is applied to the surface of the balloon bywinding a wire helically around the balloon.
 29. Method according toclaim 18, whereby the relief structure is applied to the surface of theballoon by winding a wire helically around the balloon.
 30. Methodaccording to claim 17, whereby the relief structure is applied to thesurface of the balloon by winding a wire helically around the balloon.31. Method according to claim 16, whereby the relief structure isapplied to the surface of the balloon by winding a wire helically aroundthe balloon.
 32. Method according to claim 15, whereby the reliefstructure is applied to the surface of the balloon by winding a wirehelically around the balloon.
 33. Method according to claim 14, wherebythe relief structure is applied to the surface of the balloon by windinga wire helically around the balloon.
 34. Method according to claim 13,whereby the relief structure is applied to the surface of the balloon bywinding a wire helically around the balloon.
 35. Method according toclaim 12, whereby the relief structure is applied to the surface of theballoon by winding a wire helically around the balloon.
 36. Methodaccording to claim 11, whereby the relief structure is applied to thesurface of the balloon by winding a wire helically around the balloon.37. Method according to claim 10, whereby the relief structure isapplied to the surface of the balloon by winding a wire helically aroundthe balloon.
 38. Method according to claim 9, whereby the reliefstructure is applied to the surface of the balloon by winding a wirehelically around the balloon.
 39. Method according to claim 8, wherebythe relief structure is applied to the surface of the balloon by windinga wire helically around the balloon.
 40. Method according to claim 23,whereby the relief structure is applied to the surface of the balloon bytaking up the balloon in a counter-pressure body provided with therelief structure.
 41. Method according to claim 22, whereby the reliefstructure is applied to the surface of the balloon by taking up theballoon in a counter-pressure body provided with the relief structure.42. Method according to claim 21, whereby the relief structure isapplied to the surface of the balloon by taking up the balloon in acounter-pressure body provided with the relief structure.
 43. Methodaccording to claim 20, whereby the relief structure is applied to thesurface of the balloon by taking up the balloon in a counter-pressurebody provided with the relief structure.
 44. Method according to claim19, whereby the relief structure is applied to the surface of theballoon by taking up the balloon in a counter-pressure body providedwith the relief structure.
 45. Method according to claim 18, whereby therelief structure is applied to the surface of the balloon by taking upthe balloon in a counter-pressure body provided with the reliefstructure.
 46. Method according to claim 17, whereby the reliefstructure is applied to the surface of the balloon by taking up theballoon in a counter-pressure body provided with the relief structure.47. Method according to claim 16, whereby the relief structure isapplied to the surface of the balloon by taking up the balloon in acounter-pressure body provided with the relief structure.
 48. Methodaccording to claim 15, whereby the relief structure is applied to thesurface of the balloon by taking up the balloon in a counter-pressurebody provided with the relief structure.
 49. Method according to claim14, whereby the relief structure is applied to the surface of theballoon by taking up the balloon in a counter-pressure body providedwith the relief structure.
 50. Method according to claim 13, whereby therelief structure is applied to the surface of the balloon by taking upthe balloon in a counter-pressure body provided with the reliefstructure.
 51. Method according to claim 12, whereby the reliefstructure is applied to the surface of the balloon by taking up theballoon in a counter-pressure body provided with the relief structure.52. Method according to claim 11, whereby the relief structure isapplied to the surface of the balloon by taking up the balloon in acounter-pressure body provided with the relief structure.
 53. Methodaccording to claim 10, whereby the relief structure is applied to thesurface of the balloon by taking up the balloon in a counter-pressurebody provided with the relief structure.
 54. Method according to claim9, whereby the relief structure is applied to the surface of the balloonby taking up the balloon in a counter-pressure body provided with therelief structure.
 55. Method according to claim 8, whereby the reliefstructure is applied to the surface of the balloon by taking up theballoon in a counter-pressure body provided with the relief structure.56. Method for producing a balloon catheter, the method comprising:folding a balloon in an uninflated state in a manner which reduces aprofile of the balloon; and winding a wire about at least a portion ofan outside surface of the folded balloon in a direction having acomponent transverse to a longitudinal axis of the balloon.
 57. Methodaccording to claim 56, further comprising: raising an internal pressureof the balloon to a selected pressure; heating the resulting balloonstructure; and removing the wire from the balloon wherein at least onegroove has been formed in the outer surface of the balloon.
 58. Methodaccording to claim 56, wherein the wire is made of a material whichcontracts when heated.
 59. Method according to claim 58, wherein thematerial is nylon.
 60. Method according to claim 56, further comprisingpositioning a stent over the balloon prior to winding the wire about theballoon.
 61. Method according to claim 60, further comprising placing afiller material adjacent the ends of the stent prior to winding the wireabout the balloon.
 62. Method according to claim 57, further comprisingpositioning a stent over the balloon after heating the balloonstructure.